Do clever people live longer? Why is it that scientists often hit the fabled 100-year mark? Is it nature, nurture, behaviour or just luck? New research may have the answer. A new paper in the British Medical Journal suggests that our genes may explain why brainboxes live longer (and crucially, why irresponsible and silly leaders may not be around for ever…)
Intelligence is a sign of Health
Old science suggests that a high IQ means that you are more likely to behave in a way that makes you live longer. Simple things like avoiding poor diets, prioritising exercise and having a well-paid job all work together. Although this makes sense, you don’t need to be a rocket scientist to avoid burgers. The theory sounded good but ultimately falls down.
New evidence supports a rather wordy “system integrity hypothesis”. The data suggests that high IQ doesn’t lead to healthy behaviour, but is rather an indication of health. The chicken and egg argument applied to Einstein.
Hard data for a longer life
New research in support of this theory comes from the laboratory of Ian Deary, Professor of Differential Psychology at The University of Edinburgh. Through a simple follow up study measuring various factors, the authors came across some interesting findings;
- The study used data from the Scottish Mental Surveys of 1932 and 1947, which recorded the IQ test scores of almost every 11-year-old in Scotland.
- It focussed on 33,536 male and 32,229 female subjects who had participated in the 1947 survey.
- This whole year of the Scottish birth population was followed into adulthood and the cohort’s 68-year death data used to investigate any association between childhood IQ and future health.
- The study found that higher scores in a childhood intelligence test were associated with lower risk of mortality ascribed to coronary heart disease and stroke, cancers related to smoking, respiratory diseases, digestive diseases, injury, and dementia.
- This link, seen in both men and women, persisted even when factors such as higher incomes and smoking were accounted for.
But we can’t be too sure…
Such studies have contributed to a new field of research, cognitive epidemiology, exploring the role of childhood intelligence as a risk factor for adult health. The problem in identifying such a relationship, however, is the difficulty of teasing out every other possible driver of the association, most notably variation in lifestyle choices between different demographics. Additionally, we must question whether IQ test scores are really representative of intelligence. IQ tests do not take into account the structural and economic conditions of poverty, for example.
The “system integrity hypothesis” is therefore very difficult to evaluate given the multifaceted link between intelligence and health. It is very possible that there are other factors at play which we are unaware of.
Past literature is clear in its suggestion that intelligence and health are linked. Socioeconomic status, which is influenced by IQ, is known to be a driver of this link. However, the question of whether genetics is the invisible hand behind both a high IQ and a healthy physiology remains.
Images courtesy of pixabay
1. Does IQ explain socioeconomic inequalities in health?. (2006). BMJ, 332(7541), pp.0-b-0.
2. Arden R, Luciano M, Deary IJ, et al. (2016). The association between intelligence and lifespan is mostly genetic.
3. Calvin, C., Batty, G., Der, G., Brett, C., Taylor, A., Pattie, A., Čukić, I. and Deary, I. (2017). Childhood intelligence in relation to major causes of death in 68 year follow-up: prospective population study.
4. The Independent. (2017). Smart people live longer, according to new research. [online] Available at: http://www.independent.co.uk/life-style/health-and-families/health-news/clever-people-live-longer-less-intelligent-research-british-medical-journal-bmj-a7835701.html [Accessed 14 Jul. 2017].
5. En.wikipedia.org. (2017). Cognitive epidemiology. [online] Available at: https://en.wikipedia.org/wiki/Cognitive_epidemiology [Accessed 14 Jul. 2017].